Stable Isotope Facility
University of Wyoming
Application of Stable Isotope Measurements
The application of Stable Isotopes measurements can be used to integrate, indicate,
record and trace fundamental ecological processes. Rapid technological advances over
the past decade have greatly stimulated the use of isotope analyses by ecologists.
This analytical approach is now among the most popular in ecology because of the insights
provided by isotope ratios at natural abundance levels.
- Isotopes integrate ecological processes in space and time. The isotope ratios of plant
and animal tissues and organic and inorganic compounds (including gases) in soil represent
a temporal integration of significant physiological and ecological processes on the
landscape. The timescale of this integration depends on the element turnover rate
of the tissue or pool in question. In addition, the isotope ratios of well-mixed environmental
reservoirs, such as the atmosphere, streams and aquifers, often represent an integration
of source inputs to the system that extend over large spatial scales.
- Isotopes indicate the presence and magnitude of key ecological processes. Many ecological
processes produce a distinctive isotope fingerprint. The presence or absence of such
processes and even their magnitude in relation to other processes are indicated by
the stable isotope ratio value relative to known background values.
- Isotopes record biological responses to Earth’s changing environmental condition.
For cases in which substances or residues accumulate in an incremental fashion, such
as in tree rings, animal hair and ice cores, isotope ratios can be used as a record
of system response to changing environmental conditions or a proxy record for environmental
change.
- Isotopes trace the origin and movement of key elements and substances. Owing to isotopic
fractionations associated with physical and biological reactions, nutrient and element
pools within and among ecosystems often differ isotopically. As a result, the source(s)
of essential elements and resources acquired by an organism are easily traced using
isotope ratios. Strong geographic patterns in isotope signature variation provide
the means to trace the movement or origin of a substance or component at landscape
to continental scales.
